U.S. Pat. No. 4,128,495 discloses bleaching compositions comprising phthaloyl peroxide and sodium perborate. Phthaloyl peroxide is a peroxyacid precursor and is hydrolysed or perhydrolysed in aqueous medium to produce monoperoxyphthalic acid or diperoxyphthalic acid. Detergent and/or bleaching compositions comprising organic peroxyacids, such as diperoxyisophthalic acid, are also known from e.g. British Pat. Nos. 1,387,167; 1,456,591 and U.S. Pat. No. 4,100,095.
British Pat. No. 1,269,677 discloses bleaching compositions comprising a percarboxylic acid, e.g. perbenzoic acid, and an inorganic persulphate, particularly the mixed salt KHSO.sub.4, K.sub.2 SO.sub.4, 2KHSO.sub.5.